Hemiplegic CP affects only one side of the body, and the condition is estimated to affect approximately 1 in 1,300 live births. People generally think cerebral palsy is caused by physical factors such as birth asphyxia, stroke, or infection of the developing fetal brain. Now, this new research suggests that genetics may also play a role in the cause of hemiplegic CP.

Researchers analyzed DNA from nearly 100 children with hemiplegic CP and their biological parents, and compared it to DNA from normal population controls. The team identified specific genetic alterations called copy number variants (CNVs) in several genes important for brain development and function.

Some of these CNVs occur randomly while other CNVs can be inherited — although rarely — from the parents. Combining both new and inherited CNVs, these genetic alterations were found in over 20 percent of hemiplegic CP cases. Researchers attributed these CNVs to the cause of hemiplegic CP in about 5 percent of the cases.

“We are getting closer to understanding the complex biology of CP and the potential ‘brain development’ genes that impact a child’s risk of developing it,” Darcy Fehlings, senior clinician scientist at Holland Bloorview Kids Rehabilitation Hospital in Toronto and principal investigator at CP-NET, said in a press release.

“Findings support a strong genetic link to the cause of hemiplegic CP, which affects 35 percent of kids with CP,” Fehlings added. “Clinically this supports the use of genomic testing as part of forming the work-up for a child with hemiplegic CP. In the future, understanding the genetic basis of CP may lead to the development of new treatment approaches.”

The study shows that genetics can play an important role in the development of cerebral palsy during fetal development, and it raises questions about the role of genetic testing. Genetic testing would offer parents, as well as physicians, more information about the reasons why a child may develop CP. This knowledge could also lead to better treatments.

“The discovery of a genetic link to CP not only demonstrates progress in understanding the condition better, but also highlights the benefit and need for increased research collaboration,” said Tom Mikkelsen, president and scientific director at the Ontario Brain Institute.

“To find definite answers and effective treatments, we need to come together as a neuroscience community in order to maximize impact and improve the lives of people living with brain disorders,” he said.